Heat exchanger envelope comprising assembled channels and plates



w. E. HAMMOND ET AL HEAT EXC ER ENVELO ASSEMB File Aug. 25, 1953 PECOMPRI I G CHANNELS AND- PLAT d June 8 1951 d fl y mm Q m W50 7 M2 C V.B

Patented Aug. 25, 1953 HEAT EXCHANGER ENVELOPE COMPRISHVG ASSEMBLEDCHANNELS A ND PLATES William E. Hammond, Wellsville, and Clayton A.Ballard, Belmont, N. Y., assignors to The Air Preheater Corporation, NewYork, N. Y.

Application June 8, 1951, Serial N 0. 230,544

4 Claims.

The present invention relates to improvements in plate type exchangersutilized for the transmission of heat between two confined fluids andparticularly to an improved "envelope component to be assembled inmultiples in forming such a heat exchanger.

A well known type of apparatus for the transfer of heat between twoconfined fluids is made up of a plurality of spaced metallic platesforming passages through alternate ones of which a relatively hot gasflows in heat exchange relationship with air'or other fluid to be heatedthat traverses the intermediate passages. In many such exchangers aseries of fenvelopes are provided each consistin of a pair of parallelplates with the space therebetween closed along one pair of oppositeedges to bound the sides of the passage for oneof the fluids such as airto be heated. The envelopes are mounted in spaced parallel relation toform therebetweenv the. passages for the other fluid or heating gas andthe inter-envelope spaces are likewise closed along one pair of oppositeside edges of the envelopes, which sides may be those extending parallelto the closed edges ofthe air envelopes in case of parallel flow, oralong the adjacent sides in case of transverse flow. Such spacedenvelopes form a core that is usually enclosed within a housing withwhich are associated the inlet and outlet manifolds and the supply anddischarge ducts for the two fluids.

' To increase the heat transfer efliciency heat exchangers of thistype"frequently have the walls of the fluid passages provided with extendedsurface in the form of fins projecting from the plates forming thepassage walls into the path of the fluids and serving to increase theconduction of heat to and through the walls bounding the passages. Inthe application of Sven I-Iolm, Serial No. 752,008, dated June 3, 1947,now Patent No. 2,595,457, dated May 6, 1952, there is disclosed a formof extended surface for passage walls comprising pin-like fins extendingbetween the walls bounding the gas passage. on the opposite face ofthese walls extended surface is provided in the form of channel membersextending parallel to the direction of air flow. To promote suflicientheat transfer good bonds have to be provided between the pin finelements on the inner walls of the gas passage and also between theouter walls of this passage and the channel members and such bonds haveheretofore been provided by brazing.

The present invention is directed to an improved plate assembly thatforms the passage walls and the fin elements that constitute extendedsurface from these walls so as to form an integral heat exchangeenvelope.

The invention will best be understood upon consideration of thefollowing detailed description of illustrative embodiments thereof whenread in conjunction with the accompanying drawings in which:

Figure 1 is a perspective view of a heat exchanger envelope composed ofa series of structural elements assembled and bonded together inaccordance with the present invention;

Figure 2 is an end view of the envelope shown in Figure 1 and Figure 3is a View similar to Figure 1 of a modified form.

The heat exchanger envelope shown in Figure 1 is made up of two parallelrows of U-shaped channel members I 0 assembled in side by side relationin rows 50 that the bases 12 of the channels aline to form the walls ofthe fluid passage l4 within the envelope. The side legs I6 of thechannel members are spaced apart and interposed between the latter areplates 20 that project from the passage walls so as to subdivide thelatter, the longitudinal edges 22 of the plates 20 being in the plane ofthe longitudinal edges 24 on the end faces of the legs 01 the channelmembers so that the plates and channels may be welded into a unitaryenvelope by forming welds longitudinally along the alined faces of thechannel legs l6 and plates 20. The channel legs l6 and parts of plate 20between them constitute longitudinal or strip fins in the air passage.Tabs 32 bent from perforations 34 in the plates 20 provide additionalsurface in the gas passage for absorbing heat and conducting it throughparts of the plates 20 to the walls of the gas passage constituted bythe bases l2 of channels to. As shown in Figure 1 the row of openings 34is punched in a plate 20 so that the lower marginal edges of the plates32 lie below the base l2 of the channel member in order that the fintabs 32 may be symmetrically located in the gas passage.

The arrangement in Figure 3 is similar except that rows of perforations31 and 3B are formed in staggered relation in the plates and the tabs 40are bent from the lower margins of the perforations 31 so as to lie inthe same plane as and aline with the tabs 42 struck from the upper edgesof the perforations 38.

The staggered arrangement of perforations in Figure 3 has the advantageof enabling the formation of longer fin tabs 40, 42 while at the sametime maintaining the tabs located in a central plane in the passage.This increased tab length is possible since the perforation from which atab is struck may be of greater height than in Figure 1 and beoverlapped further by the legs or flanges of the adjacent channels.

Along the longitudinal side edges of the envelopes imperf-orate platessuch as indicated at 36 in Figure 3 would be utilized to close the sideof the gas passages. By mounting a series of envelopes in spacedrelation aplate heat exchanger may be formed with alternate passages forgas and intermediate passages for air. These passages being connected attheir ends to manifolds which divide the air and .gas into streamsflowing within the interior of the envelopes and within the spacesbetween them respectively.

What We claim is:

l. A heat exchanger envelope comprising a contact with the outer facesthereof and projecting beyond the bases of the channels in .said row toextend between the side legs of similar channel U-shaped membersdisposed in .inverted relation in the opposite row with the end faces ofsaid plates located in the plane of the longitudinally extending endfaces of the legs of the channel members in both rows; and longitudinalwelds along the end faces of said plates and channels uniting themtoform a unitary envelope with longitudinal fins on its outer Wallsconstituted by the legs of said channel members and the interveningportions of said plates.

2. A heat exchanger envelope comprising a plurality of U-shaped metallicchannel members mounted in closely spaced side by side relation so thatthe channel bases aline in each row to form opposite wall of a fluidpassage within the envelope and disposed in two parallel rows with theirbases in confronting relation to form the boundary wall of said passageand with their legs extending from the :outer faces of the envelope aslongitudinal fin parts; plane plate members interposed between the sidelegs of adjacent channel members in one row in contact with the outerfaces thereof and projecting beyond the bases of the channels in said.row to 4 extend between the side legs of similar channel U-shapedmembers disposed in inverted relation in the adjacent row with the endfaces of said plates located in the plane of the longitudinallyextending end faces of the legs of the channel members in both rows; andlongitudinal welds joining along the end faces of said plates andchannels forming a unitary envelope with longitudinal fins on its outerwalls constituted by the legs of said channel members and the interveninportions of said plates.

3. A heat exchanger envelope comprising a plurality of U-shaped metallicchannel members mounted in closely spaced side by side relation inupright and inverted relation in either of two parallel rows so that thechannel bases aline in each row .to form parts of opposite walls of afluid passage located between the two rows of channel members; planeplate members interposed between the side legs of contiguous uprightU-shaped channel members in one row in contact with the outer facesthereof and projecting beyond the .bases of the channels in said .row toextend between .the side legs of similar :channel U-shaped membersdisposed in inverted relation in the opposite row with the end faces ofsaid plates located in the plane of the longitu dinally extending endfaces of the legs of the channel members in both rows; and longitudinalwelds along the end faces of said plates and channels uniting them toform a unitary envelope with longitudinal fins on its outer wallsconstituted by the legs of said channel members and the interveningportions of said plates; and rows of tabs punched from the material ofsaid plate members and extending therefrom into the passage formed bysaid rows of said channel members.

4. A heat exchanger envelope as defined in claim 3 wherein the tabspunched from the plate material are bent to lie in a plane parallelingthe passage walls and extend into the passage from opposite margins ofperforations arranged in staggered relation in parallel rows extendinglongitudinally of said vplates.

WILLIAM E. HAMMOND. CLAYTON A. BALLARD.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,705,471 De Beauvais Mar. 19, 1929 1,775,819 Fischer et alSept. 16, 1930 2,321,110 Shipman June 8, 1943

